Arc-extinguishing structure and tank housing for a compressed-gas circuit interrupter



3,246,108 SING TER 3 Sheets-Sheet 2 Aprll 1966 R. e. COLCLASER, JR.,ETAL ARC-EXTINGUISHING STRUCTURE D TANK H FOR A COMPRESSED-GAS CIRCUINTER Filed Feb. 15, 1961 Fig. 5

111 1111 I IIIIIIIIIIIIIIIIIIIIIIIII I III April 12, 1966 co c s JR ETAL3,246,108

ARC-EXTINGUISHING STRUCTURE AND TANK HOUSING FOR A COMPRESSED-GASCIRCUIT INTERHUPTER Filed Feb. 15, 1961 5 Sheets-Sheet 5 HIGH PRESSURECLOSE M OPEN 75 MAN-E Fig 6 United States Patent 3,246,108ARC-EXTINGUISHING STRUCTURE AND TANK HOUSING FOR A COMPRESSED-GASCIRCUIT INTERRUPTER Robert G. Colclaser, Jr., and Russell N. Yeckley,Monroeville, Pa., assignors to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 15, 1961, Ser.No. 89,495 Claims. (Cl. 200-148) This invention relates to circuitinterrupters in general and, more particularly, to arc-extinguishingstructures and operating mechanisms therefor.

In the relatively low-voltage, high-current class of breakers,gas-filled structures offer several important advantages overconventional oil circuit breaker structures. At the present time, oilcircuit breakers are generally of the self-generated pressure type,which are relatively ineffective at low currents, such as transformermagnetizing currents, or line-charging currents. As well known by thoseskilled in the art, whenever an interrupter depends upon self-generatingaction for the achievement of adequate interrupting pressure, difficultyis invariably encountered when interrupting low-amperage currents, whenthe self-generating pressure is low. The requisite pressure, necessaryfor interruption of such low currents, is, therefore, difiicult toobtain. On theother hand, with a compressed-gas circuit interrupter, thepressure of the blasting action, and the duration of the blast isindependent of the magnitude of the current being interrupted. Suchcompressed-gas circuit interrupters are, as a consequence, inherentlymore suitable for the interruption of low-current arcs than areoil-circuit interrupters, in which there exists the difliculty ofobtaining adequate in terrupting pressure by the aforesaidself-generating action.

It is, accordingly, a general object of the present invention to providean improved circuit interrupter for relatively low voltages, say 34.5kv., and suitable for interrupting a wide range of currents, in whichrelatively high-pressure gas, for example sulfur hexafluoride (SP gas,at a pressure of, for example, 200 p.s.i.g. is used to extinguish thearc.

In the United States patent application filed October 7, 1960, SerialNo. 61,284, now Patent No. 3,154,658, by Robert G. Colclaser, Jr. andRussell N. Yeckley, and assigned to the assignee of the instantapplication, there is disclosed and claimed a novel type of interruptingunit. In the patent application referred to, this interrupting unit isemployed in conjunction with several other like units in a high-power,dual-pressure, tank-type circuit interrupter utilizing sulfurhexafiuoride (SF gas as the arcextinguishing medium.

It is a further object of the present invention to provide aninterrupting unit similar to the type set forth in the aforesaid patentapplication, which may be utilized for a lower-voltage rating in acircuit interrupter of a generally simplified type.

Still a further object of the present invention is to provide animproved quickly-operated blast-valve mechanism, which may beimmediately opened, by a novel construction, at the beginning of theopening operation.

Still a further object of the present invention is to provide animproved operating mechanism particularly suitable for a circuitinterrupter of the type set forth above.

Yet another object of the present invention is to provide an improvedcompressed-gas type of circuit interrupter of compact size and simpleconstruction particularly suitable for multi-pole operation.

Further objects and advantages will readily become apparent upon readingthe following specification taken in conjunction with the drawings, inwhich:

FIGURE 1 is an enlarged vertical sectional view taken substantiallyalong the line II of FIG. 2, taken through a tank-type circuitinterrupter embodying features of the present invention, with thecontact structure illustrated in the closed-circuit position;

FIG. 2 is a somewhat smaller longitudinal vertical sectional view takenthrough the tank-type circuit interrupter of FIG. 1, generally along theline II-II of FIG. 1, and illustrating the three pole-units disposed inthe single tank structure;

FIG. 3 is a fragmentary view, somewhat similar to that of FIG. 1, butillustrating the position of the several contact parts in the fullyopen-circuit position;

FIG. 4 is an enlarged vertical sectional view taken along the line IV-IVof FIG. 1;

FIG. 5 is a vertical sectional view taken through the blast-valvemechanism of the present invention, the valve structure beingillustrated in the closed position; and,

FIG. 6 is a somewhat diagrammatic view illustrating the operatingmechanism for the circuit interrupter of the present invention, theseveral parts being shown in the closed-circuit position.

Referring to the drawings, and more particularly to FIGURE 1 thereof,the reference numeral 1 generally indicates a compressed-gas circuitinterrupter. As shown, the interrupter 1 includes a groundedsubstantially cylindrical tank structure 2 enclosing an interruptingunit 3 supported from the lower interior ends of the pair of terminalbushings 4, 5. As shown in FIG. 2, a plurality of pole-units A, B and Care housed within the tank structure 2, and are simultaneously operatedby a rotatable operating shaft 6, which extends through a seal 7 (FIG.2) and is actuated externally of the tank structure 2 by meanshereinafter described.

As shown in FIG. 1, a pair of current transformers 8, 9 may encircle themounting supports 10, which are preferably welded, as at 11, to the tankstructure 2. By having the current transformers 8, 9 encircle theterminal bushings 4, 5, differential protective relaying is obtainedwithout any expensive complicated structure.

As shown in FIG. 6, a high-pressure reservoir tank 12 contains gas, suchas sulfur hexafluoride (SP gas at a relatively high pressure, say 200p.s.i.g. A blast tube 13 extends upwardly from the high-pressure tank12, and the blasting of high-pressure gas through the blast tube 13 iscontrolled by the operation of a blast valve, generally designated bythe reference numeral 14, and shown more specificially in FIG. 5 of thedrawings.

Returning to FIG. 1, rotation of the operating shaft 6 in a clockwiseopening direction, rotates therewith a crank-arm 15, which is pivotallyconnected, as at 16, to an insulating operating rod 17, the latter beingconnected, by a pivot pin 18, to an operating crank 19. The operatingcrank 19 is journaled, by a pivot pin 20, to an end casting 21,constituting a portion of the interrupting unit 3.

The operating crank 19 has integrally formed therewith a pair of forkedlevers 22, as shown in FIG. 4. The ends of the forked levers 22 arebifurcated, as at 23, and straddle guide pins 24, secured to a movablecontact 26. The guide pins 24 move in race tracks 25 integrally formedwith the end casting 21.

It will be apparent from the foregoing, that clockwise rotation of theoperating crank-arm 15 will, through the linkage 17, 19, effect leftwardopening movement of the tubular movable contact 26. As shown in FIG. 1,the right-hand end 27 of the movable contact 26 makes contactingengagement with a pair of contact fingers 28, positioned within acontact support 29, and biased radially inwardly by compression springs30. The con-tact support 29 is, as shown, a part of a second end castingor contact housing 31, which, additionally, supports an arcing horn 32,to which the arc is transferred in a manner more particularly broughtout hereinafter.

Interconnecting the end castings 21, 31 is a substantially cylindricalinsulating interrupter casing 33. As shown in FIG. 1, the cylindricalinterrupter casing 33 may have associated therewith aninternally-disposed liner 33a, which preferably is formed frompolytetrafluoroethylene. Disposed intermediate the ends of thecylindrical interrupter casing 33 is a plate 34 having an orificeopening 35. As shown in FIG. 3, the movable tubular contact 26 moveslongitudinally of the orifice opening 35 to a fully open-circuitposition being guided by the opening 35 of plate 34 and also by atetrafiuoroethylene guide sleeve 33b. The plate 34 in combination withthe liner 33a, forms an interrupting chamber 43.

To assist in effecting the extinction of the are 36, which extendsbetween the arcing horn 32 and the interior surface 37 of the movablecontact 26, the present invention employs a blast of gas transmittedupwardly interiorly of the blast tube 38 interconnecting the region 39within unit 3 with the region 40 interiorly of a manifold 41. Themanifold 41 extends lengthwise of the tank structure 2, in a manner moreclearly shown in FIG. 2 of the drawings. Thus, actuation of theblast-valve mechanism 14 will permit a blast of high-pressure gas fromthe tank 12 to flow upwardly through the blast tube 13, into theinterior 40 of the manifold 41, and upwardly through the several blasttubes 38 (FIG. 2) and into the several regions 39 associated with theinterrupting units 3 of the pole-units A, B and C.

This blast of gas, which is suitably timed, as more fully brought outhereinafter, is ejected from the region 39, through an orifice opening42, and into the arcing chamber 43, defined by the interior liner 33aand the orifice plate 34. The blast of gas passes longitudinally throughthe interior of the tubular movable contact 26, and is exhaustedexternally of the interrupting unit 3 in a manner more clearly indicatedby the arrows 44 in FIG. 3. To resist the possible corrosive action ofthese gases exhausting against the tank structure 2, preferably apolytetrafluoroethylene pad 45 is employed, as shown in FIG. 3.

The terminal bushings 4, supporting the interrupting unit 3, preferablyare of the gas-filled type, as more fully set forth in United Statespatent application filed December 2, 1959, Serial No. 856,775, nowPatent No. 3,059,- 044, by Robert E. Friedrich and James H. Frakes, andassigned to the assignee of the instant application.

In the closed-circuit position of the circuit interrupter 1, asillustrated in FIG. 1, the electrical circuit therethrough includesterminal connection 46, terminal stud 47, lower adapter 48, end casting21, contact fingers 28, movable tubular contact 26, right-hand contactfingers 28, interrupter adapter 49, terminal stud 50, to line terminalconnection 51.

During the opening operation, with reference being particularly had withrespect to FIG. 6, the open or trip button 52 is manually pusheddownwardly. Naturally, as well known by those skilled in the art,suitable electrically-actuated overload devices, responsive to thecurrent passing through the current transformer 8, 9, may be substitutedfor the trip button 52, or employed additionally therewith.

The manual closing of the trip button 52 will bridge the contacts 53 andcomplete a circuit 54 to energize the electromagnetically-actuatedblast-valve mechanism 14. The energization of the coil 55 will move thearmature 56, and hence the plunger 57 downwardly, as viewed in FIG. 5.The plunger 57 will contact the button 58 (FIG. 5) associated with thepilot valve 59, forcing the later downwardly in opposition to thepressure exerted by a compression spring 60 and a slightly unbalancedgas pressure. he opening of the pilot valve 59 will dump the pressurefrom the region 61 behind the main blast valve 62 to the region 40,which is at relatively low pressure.

The dumping, or exhausting of the region 61 to low pressure will permitthe high pressure within the region 64 (FIG. 5) to act downwardly on themain blast valve 62, forcing the latter downwardly against theopposition afforded by a second compression spring 65. The opening ofthe main blast valve 62 will permit high-pressure gas passing upwardlythrough the blast tube 13 to fiow into the manifold structure 41 and tothe several blast tubes 38 associated with the several pole-units A, Band C.

With further reference to FIG. 6, it will be noted that not only doesthe manual closing of the trip button 52 energize the circuit 54 leadingto the blast-valve mechanism 14, but also the closing of the trip button52 will energize a circuit 66, which will energize the coil 67 of adelayed-acting relay 68. Following a suitable time delay, the bridgingcontact 69 will close the contacts 70 of delay-action relay 68, andthereby energize the circuit 71 energizing anelectromagnetically-actuated latching device 72. The energization of thecoil 73 of the latching device 72 will release the latch 74 from a catch75 provided along the side of a piston rod 76. This will permit acompression spring 77 to move a piston 78, and hence the piston rod 76in a rightward direction, as viewed in FIG. 6. The piston rod 76 ispivotally connected, as at 79, to an externally disposed crank-arm 88,the lower end of which is keyed to the rotatable operating shaft 6.

The rotation of the operating shaft 6 efiects opening of the severalmovable contacts 26, in the manner pointed out above, and the passing ofthe high-pressure gas through the several blast tubes 38 and into theinterrupting units 3, and out through the tubular contacts 26 willeffect rapid extinction of the arcs 36 in a manner more fully broughtout in the aforesaid Colclaser and Yeckley patent application. Morespecifically, the right-hand terminal of the are 36 is transferred fromthe conducting orifice opening 42 to the arc horn 32, as shown in FIG.3. The left-hand end of the are 36 is blown along the inside surface ofthe tubular movable contact 26.

The rightward opening movement of the piston rod 76 will be open up aninterlock switch 81 (FIG. 6), and will thereby deenergize the coil 55 ofthe blast-valve mechanism 14. Referring to FIG. 5, this well permithighpressure gas within the region 64 to pass through side openings 82in the blast valve 62 and into the region 61. This fact, coupled withthe spring action exerted by the compression spring 60, will effectreclosure of the pilot valve 59 and consequent reclosure of the mainblast valve 62. The closing of the main blast valve 62 will halt thepassage of high-pressure gas out of the interior 40 of the manifold 41and through the blast tube 38. The pressure will then drop in the region40 to the same pressure as that present in the region 83 interiorly ofthe main exhaust tank structure 2.

It will be obvious that following a plurality of opening operations, thepressure within the region 83 within the tank structure 2 will beraised, and, consequently, the pressure within the storage tank 12 willbe correspondingly lowered. A pressure switch 84 will reflect this stateof affairs, and will start up a compressor unit 85. The compressor unit85 will extract gas from the exhaust tube 86 and force the recompressedgas through the inlet 87 back into the high-pressure reservoir tank 12.When the pressures within the high-pressure tank 12 and the exhaust tank2 have attained their desired values, suitable means, well known tothose skilled in the art, will be effective to deenergize the compressorunit 85.

To effect closing of the circuit interrupter 1, a closing button 88 maybe pressed. This will bridge the contacts 89 and will energize a circuit90, which will energize an electromagnetically-actuated valve 91. Theopening of the valve 91 will permit high-pressure gas to pass from aconduit 92 into one end 93 of an operating cylinder 94 to act upon thepiston 78 and force the same leftwardly toward the left-hand end of theoperating cylinder 94. When the catch 75, carried by the piston rod 76,reaches the position illustrated in FIG. 6, the latching device 72 willbe elfective to hold the piston rod 76 in this closedcircuit position.

It will be noted that the region 95, to the left of the piston 78,communicates through a low-pressure connecting tube 96 with the exhausttank 2, which is, of course, at low pressure.

While the valve 91 is open, the high-pressure gas will pass through thepipe 97 and effect closing of a valve 98 over an opening 99. This willprevent substantial bleeding of high-pressure gas through bypass conduit102. When the valve 91 is deenergized, by release of the closing button88, the presence of the relatively small bypassing conduit 100 willpermit pressure within the region 93 to be rapidly lowered. This willenable the compression spring to effect reopening of the dump valve 98and permit a rapid dumping, or exhausting action to take place throughthe opening 99 and relatively large exhaust pipe 102.

From the foregoing description, it will be apparent that there isillustrated and described an improved compressed-gas type of circuitinterrupter particularly adapted for relatively low voltages, Where asingle interrupting unit 3 may be adequate. The interrupting unit 3employs high-pressure sulfur hexafluoride (SP gas at, say a pressure of200 p.s.i.g. to extinguish the arcs 36. This interrupter 3 isparticularly efficient at low currents of any nature and has proveninterrupting ability. It has interrupted 44,000 amperes with no externaldemonstration.

By disposing the three pole-units A, B and C within a single exhausttank structure 2, a relatively compact circuit-interrupting device 1 isobtained.

As was the case with United States patent application Serial No. 50,183,filed August 17, 1960, now abandoned, by Robert G. Colclaser, Jr., andFrank L. Reese, and as signed to the assignee of the instantapplication, the sulfur hexatluoride gas may not only be used to effectextinction of the established arcs, but also may be used to effectoperation of the operating mechanism 103 set forth in FIG. 6 of thedrawings.

The electromagnetically-actuated blast-valve device 14 is very rapidlyopened by energization of the solenoid 55. This action is even fasterand more efiective than employing a pneumatically-actuated pilot-valvein connection with a blast-valve device.

It is to be noted that the end castings 21, 31, of the interrupting unit3 are constructed to be identical before machining. Thus theinterrupting unit 3 is made up of simple and common parts where possiblefor economy. Since the high-pressure reservoir tank 12 is at groundpotential and located, preferably, below the interrupting tank 2, noproblem is encountered in supplying heat to the tank 12 to prevent thegas from liquefying in cold weather.

From the foregoing, it will be apparent that there is disclosed asingle-tank, dual-pressure, gas-filled, low-voitage line of circuitbreakers, which incorporate a proven interrupter unit 3. The interrupterunits 3 are constructed economically, using common components wherepossible. High-pressure gas is supplied by a quick-acting,electrically-operated blast valve. The breaker mountings 10 on the tankpermit the incorporation of through-type bushing current transformers 8,9, which are, as is well known, economical.

Certain features of the terminal-bushing mounting con- 6 struction areset forth and claimed in United States patent application filed February15, 1961, Serial No. 89,496, by Russell E. Frink, and assigned to theassignee of the instant application.

From the foregoing description, it will be apparent that because of theprovision of a blast of gas exerted over a time interval, allindependent of the magnitude of the current being interrupted, thereresults a circuit interrupter of improved construction and adaptable foreflicient operation over a wide current range, including relatively lowcurrents, with which oil circuit interrupters have difficulty, aspointed out above.

Although there has been disclosed and described a specific interrupterstructure, it is to be clearly understood that the same was merely forthe purpose of illustration, and that changes and modifications mayreadily be made therein by those skilled in the art, without departingfrom the spirit and scope of the invention.

We claim as our invention:

1. A compressed-gas circuit interrupter including a grounded tank, apair of terminal bushings extending into said tank and at leastpartially supporting an arc-extinguishing unit at their interior ends, amovable tubular contact cooperable with a relatively stationary contactto establish an arc and for receiving a blast therethrough, crank meansassociated with said movable tubular contact to effect the actuation ofthe same, and means including a stationary orifice plate disposedintermediate the ends of said unit for directing a blast ofhigh-pressure gas through said movable tubular contact to effectextinction of the are.

2. The combination in a dual-pressure compressed-gas circuit interrupterof a grounded exhaust tank, a pair of terminal bushings extending intosaid tank and at least partially supporting an are-extinguishing unit attheir interior ends, said unit having a stationary orifice plateintermediate the ends thereof, a movable tubular contact cooperable witha relatively stationary contact and movable through said orifice plateto establish an arc, crank means associated with said movable contact toeffect the actuation of the same, a separate high-pressure reservoirtank, blast-valve means for releasing a blast of gas from thehigh-pressure tank into the arc-extinguishing unit to effect extinctionof the established arc, and the exhausted blast of gas being collectedwithin the outer exhaust tank.

3. A compressed-gas circuit interrupter including a grounded tank, apair of terminal bushings extending into said tank and at leastpartially supporting an arc-extinguishing unit at their interior ends, amovable tubular contact cooperable with a relatively stationary contactto establish an arc and for receiving a blast of gas therethrough, crankmeans associated with said movable contact to effect the actuation ofthe same, a rotatable operating shaft extending along the wall of thetank, linkage means interconnecting the shaft and said crank means, andmeans including a stationary orifice plate disposed intermediate theends of said unit for directing a blast of high-pressure gas throughsaid movable tubular contact to effect extinction of the are.

4. The combination in a dual-pressure compressed-gas circuit interrupterof a grounded exhaust tank, a pair of terminal bushings extending intosaid tank and at least partially supporting an arc extinguishing unit attheir interior ends, said unit having a stationary orifice plateintermediate the ends thereof, a movable tubular contact cooperable witha relatively stationary contact and movable through said orifice plateto establish an arc, crank means associated with said movable contact toeffect the actuation of the same, a separate high-pressure reservoirtank, blast-valve means for releasing a blast of gas from thehigh-pressure tank into the arc-extinguishing unit to effect extinctionof the established arc, the exhausted blast of gas being collectedwithin the outer exhaust tank, and a rotatable operating shaft extendingalong a wall of the exhaust tank to actuate the crank means.

5. A blast-valve mechanism including a main blast valve having anexhaust opening therethrough, a pilot valve disposed in said exhaustopening for dumping the pressure in back of the main blast valve, and asolenoid plunger for directly striking the pilot valve and elfectingimmediate opening of the same.

6. A blast valve mechanism including means defining a high pressureregion, a main blast valve disposed in the high pressure region andcontrolling an outlet opening therefrom, said main blast valve having anexhaust opening therethrough, a pilot valve disposed in said exhaustopening for dumping high pressure gas from in back of the main blastvalve through said exhaust opening, and an electromagnetically actuatedsolenoid plunger disposed down stream of the outlet opening for directlystriking the pilot valve and thereby eifecting immediate opening of thesame.

7. A muiti-pole compressed-gas circuit interrupter including a generallyhorizontally extending exhaust tank structure, a plurality of pole-unitsdisposed within the exhaust tank structure, each pole-unit including apair of terminal bushings and an arc-extinguishing unit supportedthereby, an elongated manifold extending lengthwise along one wall ofthe exhaust tank structure, an insulating blast tube extending from saidelongated manifold to each arc-extinguishing unit, a high pressurereservoir tank, and blast-valve means interconnecting the manifold andthe high-pressure reservoir tank.

8. A multi-pole compressed-gas circuit interrupter including a generallyhorizontally extending exhaust tank structure, a plurality of pole-unitsdisposed within the exhaust tank structure, each pole-unit including apair of terminal bushings and an arc-extinguishing unit supportedthereby, an elongated manifold extending lengthwise along one wall ofthe exhaust tank structure, an insulating blast tube extending from saidmanifold to each arcextinguishing unit, a high pressure reservoir tank,blastvalve means interconnecting the manifold and the highpressurereservoir tank, a movable contact associated with each unit, crank meansfor actuating the movable contact to the open and closed circuitpositions, and a rotatable operating shaft extending generally parallelto said elongated manifold for operating the several crank means of thepole-units.

9. A multi-pole compressed-gas circuit interrupter including a generallyhorizontally extending exhaust tank structure, a plurality of pole-unitsdisposed within the exhaust tank structure, each pole-unit including apair of terminal bushings and an arc-extinguishing unit supportedthereby, an elongated manifold extending lengthwise along one wall ofthe exhaust tank structure, an insulating blast tube extending from saidmanifold to each arcextinguishing unit, a high pressure reservoir tank,blastvalve means interconnecting the elongated manifold and thehigh-pressure reservoir tank, a movable contact associated with eachunit, crank means for actuating the movable contact to the open andclosed circuit positions, and a rotatable operating shaft extendinggenerally parallel to said elongated manifold extending lengthwise alongone wall of the horizontally extending tank structure.

10. A compressed gas circuit interrupter including a grounded tank, apair of terminal bushings extending into said grounded tank, a pole unitcomprising a gas blast arc extinguishing unit supported by the interiorends of the terminal bushings and including a spaced pair of metallicend members and interposed insulating tubular interrupter casing, oneend metallic member having a journal portion and guide means associatedtherewith and directly supported by the interior end of one terminalbushing, the other metallic end member being directly supported by theinterior end of the other terminal bushing and having a relativelystationary contact support associated therewith, relatively stationarycontact means supported by said contact support, an apertured guidepartition plate disposed intermediate the ends of said insulatingtubular interrupter casing, a movable tubular contact at least partiallyguided by said guide means and having one end thereof separable fromsaid relatively stationary contact means to establish an are, saidmovable tubular contact being guided through the aperture of the guidepartition plate with a relatively close fit and guided thereby, crankmeans including a rotatable crank journaled by said journal portion andmechanically connected adjacent the other end of said movable tubularcontact for causing the actuation thereof, said partition plate and theportion of the tubular insulating interrupter casing between saidpartition plate and said other end metallic member comprising aninterrupter chamber, said movable tubular contact being the sole ventingmeans for said interrupter chamber to the region within the tankexternally of the arc extinguishing unit, operating means extendingbetween said crank means and the tank wall including an insulatingoperating rod to positively elfect actuation of said crank means toeffect opening and closing movement of the movable tubular contact,means forcing a blast of are extinguishing gas into said interrupterchamber during the opening operation to sweep through the interior ofsaid movable tubular contact, whereby the end of the arc will beinfluenced to move axially along the interior of the movable tubularcontact for fast interrupting action.

11. The combination of claim 10, wherein three poleunits are disposedwithin a single grounded tank, a blast manifold extends longitudinallyof the tank, said blast means comprising separate blast tubes extendingbetween the manifold and the three interrupting chambers, and saidoperating means including a rotatable operating shaft extendinggenerally parallel to said blast manifold interiorly of the tank wall.

12. A compressed-gas arc-extinguishing unit including means defining anarcing chamber, relatively stationary contact means disposed adjacentone end of said arcing chamber and including a first orifice opening(42), a stationary orifice plate (34) closing the other end of thearcing chamber and providing a second orifice opening (35) therethrough,said arcing chamber being defined by the region intermediate said twoorifice openings, said relatively stationary contact means beingdisposed on the other side of the first orifice opening from thelocation of said arcing chamber, a movable tubular venting contactmovable with slight clearance through the second orifice opening andthrough the first orifice opening into contacting engagement with therelatively stationary contact means, means for providing a blast ofarc-extinguishing gas through the first orifice opening and into thearcing chamber to exhaust out of the movable tubular venting contact,whereby an arc terminal may be carried by the blast of gas into andalong the interior surface of the movable tubular venting contact.

13. The combination according to claim 12, wherein the first orificeopening (42) is formed by a contact housing (31) for the relativelystationary contact means.

14. A compressed gas arc-extinguishing unit including an insulatingcasing and a spaced pair of metallic end members, one end member havingguide means associated therewith, the other metallic end member having arelatively stationary contact support associated therewith andconducting means providing a first orifice opening, an apertured guidepartition plate disposed intermediate the ends of the insulating casing,a movable tubular contact at least partially guided by said guide meansand having one end thereof separable from said relatively stationarycontact means to establish an arc, said movable tubular contact beingguided through the second aperture of the guide partition plate with arelatively close fit and guided thereby, means providing an arcextinguishing blast of gas through said first orifice opening, saidmovable tubular contact being the sole venting means for theinterrupting chamber to the region cxteriorly of the arc ex- 9tinguishing unit, whereby one terminal end of the arc may be swept intothe interior of the movable tubular contact for fast interruptingaction.

15. The combination according to claim 14, wherein a plurality ofcircumferentially disposed relatively stationary contact fingers aresituated immediately behind the first orifice opening.

References Cited by the Examiner UNITED STATES PATENTS 1 0 2,911,49211/1959 Beatty 200-148 2,970,193 1/ 1961 Gratzmuller 200148 2,979,5904/1961 Sandin 200-148 FOREIGN PATENTS 5 77,413 3 1949 Czechoslovakia.963,442 5/ 1957 Germany.

KATHLEEN H. CLAFFY, Primary Examiner.

10 MAX L. LEVY, ROBERT K. SCHAEFER, Examiners.

R. S. MACON, Assistant Examiner.

1. A COMPRESSED-GAS CIRCUIT INTERRUPTER INCLUDING A GROUNDED TANK, APAIR OF TERMINAL BUSHINGS EXTENDING INTO SAID TANK AND AT LEASTPARTIALLY SUPPORTING AN ARC-EXTINGUISHING UNIT AT THEIR INTERIOR ENDS, AMOVABLE TUBULAR CONTACT COOPERABLE WITH A RELATIVELY STATIONARY CONTACTTO ESTABLISH AN ARC AND FOR RECEIVING A BLAST THERETHROUGH, CRANK MEANSASSOCIATED WITH SAID MOVABLE TUBULAR CONTACT EFFECT THE ACTUATION OF THESAME, AND MEANS INCLUDING A STATIONARY ORIFICE PLATE DISPOSEDINTERMEDIATE THE ENDS OF SAID UNITS FOR DIRECTING A BLAST OFHIGH-PRESSURE GAS THROUGH SAID MOVABLE TUBULAR CONTACT TO EFFECTEXTINCTION OF THE ARC.